Summary: Suspending the building of new nuclear weapons will (a) not hurt our offensive or defensive capabilities, and (b) will significantly increase our security by improving our ability to convince other countries to stop production of nuclear weapons material and to eliminate or scale back their nuclear programs - making it harder for terrorists and their sponsoring states to acquire or build a nuclear weapon.

• 550 long-range missiles (ICBM's), with a total destructive force of more than 500 megatons,
• 18 nuclear submarines with 432 Trident missiles, with a total yield greater than 450 megatons,
• 117 strategic air bombers (B-52's and Stealth B-2's) with 950 missiles, combined together for yield larger than 150 megatons, and
• 1,123 intermediate range and short/battlefield-range missiles, with a total yield of approximately 50 megatons.

We are deeply concerned that nuclear terrorists may detonate a single, small 10-kiloton nuclear bomb.  The results of just that would be horrendous.^{3, 4, 5} A single 1-megaton bomb (such as an ICBM) is, literally, 100 times more powerful.

We have enough nuclear weapons that we can destroy in an instant any country or any combination of countries if we choose to do so.  

Building new nuclear weapons may substantially hurt our security.

One of the greatest dangers to the United States of America today is that terrorists and their sponsoring states may acquire nuclear weapons.   The Cold War has ended.  We are allies with almost every country in Europe, most of Central and South America, and much of Asia.

The greatest threat we face today - by far - is from radical terrorists, such as Al Queda and Hezbollah, and their state sponsors, such as Iran.  The best way to overcome this threat is by preventing them from acquiring nuclear weapons material.   And to do that, we need the cooperation of many countries around the world.  To help reduce this risk, we are asking other countries, such as England and Japan, to stop making material that could also be used to make their own nuclear weapons.   We are asking other countries to entirely dismantle their nuclear capabilities.

It is hard for a foreign government to convince its own people to cut back on nuclear weapons, the most powerful weapon they can have.  It is much harder for us to convince other peoples and governments to do that if at the same time we are actually increasing our own nuclear stockpile: "Do as I say, not as I do." The United States will be more effective in reducing the nuclear terrorist threat by leading: by demonstrating our commitment and resolve to this issue - by suspending building new nuclear weapons - and convincing other nations to join with us.

As the former Secretary of Defense, William Perry, recently stated:
"We have taken on the task of trying to awaken the world to incredible danger of these nuclear weapons...  All of these steps can be taken now, this year, next year, not ten years from now.  Any of these steps would make our world safer, now.  But it is also fundamental [that] international action is necessary to have any real results.  ...nearly all [of] them require international action.  International action will not be taken in the face of American exceptionalism.  [emphasis added] That is, one rule for us, and different rules for the rest of the world.  ⁶

Will our current nuclear capability be harmed by this cap?

No.

The relevant arguments are nicely summarized by Sidney Drell, professor of physics emeritus at Stanford University (Professor Drell has been a member of the President's Foreign Intelligence Advisory Board and Science Advisory Committee.  His honors include the National Intelligence Distinguished Service Medal and election to the National Academy of Sciences) and Abassador James Goodby (who has help several senior government positions focused on nuclear arms control include Deupty to the Special Advisor to the President and Secretary of State and has been the chief negotiator for nuclear threat reduction agreements.) In their report, S.  Drell and J.  Goodby, "What are Nuclear Weapons For? Recommendations for Restructuring U.S.  Strategic Nuclear Forces," October 2007, ⁷ they report that "An enhanced, multifaceted, science-based program of stockpile stewardship was established in 1994 to provide confidence to the U.S.  weapons community and, through it, to the government that ithe health of the stockpile and the way in which special bomb materials age is well understood...  Maintaining and refurbishing the [nuclear] warheads, as well as sustaining the competence of the weapons scientists, is proceeding."⁸ In fact, they argue that our nuclear deterrence would in fact be strengthened by reducing the number of nuclear warheads in the U.S.  arsenal to 1,000 by 2012.   That issue aside, current law enables the U.S.  to maintain our stockpile of nuclear weapons without producing or testing new nuclear weapons.  Moreover, they go on to argue that our current nuclear weapons can even be significantly improved within this current framework.  "One direct way to simplify the process of certifying the reliability and effectiveness of the [nuclear] warheads...  is to further enhance the explosive energy provided by the primary stage of a nuclear weapon above the minimum required...  [this] requires no explosive testing....  This approach is the appropriate focus of effort for the Reliable Replacement Warhead (RRW) program currently being funded at the U.S.  national weapons laboratories." ⁹

What about "bunker buster" missiles?

Over the past few years there has been some discussion about whether or not new nuclear weapons may be needed to destroy deeply buried hardened targets - occasionally referred to as bunker buster missiles.  This issue was raised in the 2002 Nuclear Posture Review (NPR).  After extensive discussions, in 2005 the Republican-controlled Congress concluded that such a program was not justified and should not be funded.  

First, it is important to note that the U.S.  already has a nuclear missile specially designed for bunker-busting operations: the B61-11.   This missile was designed in the mid-1990s by encasing a version of the B61 nuclear bomb in a hardened casing.

As pointed out by Drell and Goodby, "The effectiveness of warheads for destroying hardened underground targets is enhanced if their designs are sufficiently rugged so that, when delivered by aircraft of missile, they can be rammed into the earth intact and penetrate some three or more meters into the earth without damage before detonating.  Such warheads will deliver a shock to destroy an underground bunker that is 10-20 times stronger than that of the same warhead exploded at or above the earth's surface, in which case much more of its blast energy would be spend in the atmosphere.  Many hardened underground targets are at relatively shallow depths of some 30 meters, particularly large industrial targets for manufacturing weapons or producing fissile material to fuel nuclear weapons.  Other targets of very high value are more likely to be buried at depths of 300 meters or more and reinforced to withstand over-pressures of 1,000 atmospheres or more.  ¹⁰

The purpose of a new low-yield bunker buster missile would be to try and destroy these deeper hardened targets by enabling the missile to penetrate into the earth without prematurely exploding.  And it should penetrate deeply enough so that there is minimal radioactive fallout at the surface.  The formal name for this missile was RNEP - Robust Nuclear Earth Penetrator.   But, "A warhead's yield would have to be significantly larger than 100 kilotons for the shock from its blast to reach down to 300 meters with enough strength to destroy such targets.  That is certainly not a low-yield weapons.  The primitive atomic bomb that pulverized Hiroshima had a yield of only 15 kilotons."¹¹ In other words, a nuclear bunker buster missile with enough force to damage a deeply buried sight would produce significant radioactive fallout at the surface - significantly reducing the effective usefulness of such a weapon.

"What is the likely impact on U.S.  security of a new initiative for new low-yield weapons? First, the United States already [emphasis added] possesses tested and employed weapons, both conventional and nuclear, that would be effective for missions against shallow bunkers" ¹²

This perspective is shared by Admiral James O.  Ellis Jr., [at the time] head of U.S.  Strategic Command, who informed a Senate Armed Services subcommittee in April, 2003 that smart, precision-guided conventional munitions instead of nuclear weapons can be used to destroy or seal off deeply buried targets.  ¹³

As Drell and Goodby note, "The effectiveness of these weapons can be greatly enhanced by improvements in precision of delivery and in accuracy of the intelligence in locating and identifying such targets.  The United States also has a substantial ability to render hardened underground targets ineffective with conventional military systems.  These kinds of targets have vulnerable points, such as air ducts and tunnel entrances for personnel, equipment, and resources that can be sealed off by conventional munitions...  There is no credible military case for RNEP [Robust Nuclear Earth Penetrator]." ¹⁴

Finally, it is worth considering the impact developing a new nuclear weapon would have internationally and how that might affect other U.S.  efforts to reduce the threat of nuclear terrorism - a world-wide effort that be definition requires international cooperation.  "If the United States, the strongest nation in the world, concluded that is could not protect its vital interests without relying on a newly developed nuclear weapon, it would be a clear signal to other nations that nuclear weapons are necessary for their security purposes too.  That would hardly contribute to dissuading them from joining the nuclear club.  In fact, because resumed nuclear explosive testing might eventually be required for a newly designed weapon, the United States would most likely deal a fatal blow the nonproliferation regime in order to have a capability of questionable military value.  Such concerns led Congress to refuse funding for this concept in the fiscal year 2005 budget, and no new funding request has been made since." ¹⁵